Positive
by blinnn
Summary: Crabs, Casey." He paused and she stiffened for a moment, "You have crabs." Derek's avoiding; Casey's in total mood-swing mode; and- why is she straddling him, again? ONE-SHOT. WARNING: RATED M FOR A REASON. ADULT CONTENT.


WARNING: RATED M FOR ADULT CONTENT/SEXUAL REFERENCES/WHATNOT. So if you don't like it, navigate away from this page before it's TOO LATE!

Summary: "Crabs, Casey." He paused and she stiffened for a moment, "You have crabs." Derek's avoiding; Casey's in total mood-swing mode; and- why is she straddling him, again?

Author's note: I thought I'd try my hand at a smutty piece. Although... I'm pretty embarrassed, and thoroughly sure that no one will enjoy it. haha! So anywaysss. Just read and review if you'd like. Also, I had no idea what to name this fic. I wanted to name it 'Crabs' but... well it just didn't seem right to the people who... are... underage/those who may get offended. Although, the rating _is_ M so, you know. Maybe they shouldn't be lookin' at 'em anyways. haha

So I went with this title because... I'm an idiot and couldn't find anything better! :)

* * *

**Positive**

A life with Derek Fanfiction

**Disclaimer:** I certainly don't own Life with Derek.

She came blasting through his dorm room door at 1:17AM, (and he wants to _kill_ Nora and his Dad for making her an extra key in attempts to have their own make-sure-Derek's-doing-his-homework-spy).

It's not like he didn't _expect_ her to be there, (because, if he didn't he would've been asleep.) but it's really the principle of the matter.

She strode right past the empty bed that _should_ have held his roommate, (he'd been warned of an interruption, _such as this_, and had stayed elsewhere for the night) and went straight to his bed where she beat him repeatedly with a pillow that she'd apparently grabbed on her way over.

"Casey!" He yelled in a pathetic attempt to get her to just... _stop_. She paused, taking breaths that seemed too deep for her petite form, all the while glaring daggers at him.

He may have been scared, if he didn't know her better... _but he did_.

"What the _hell_ is your problem?"" He demanded an answer.

"My problem?! _MY_ problem!? What's _your_ problem?!" She replied.

"I'm... not following." He lied. I mean, _come on._ When does Derek Venturi _not_ know the reason for Casey McDonald's anger?

She scoffs, calling his bluff because _Damn her_, she knows him just as well. "Oh please, Don't play coy, Derek." The joke's on her though, because he doesn't even know what that _means_... wait. "I know you're the reason that every guy I talk to thinks I have..." She stopped herself uncomfortably.

_Figures._ Anything remotely 'R-rated' and Casey recoils.

"They think you have _what_, Casey?" His eyebrows were raised in amusement, as well as his tongue was running along the inside of his lips. He really just _enjoyed_ watching her _squirm_.

"Well... that I have..." She gestured vaguely, which just made him all the more amused, considering how insanely _hard _he was trying to bite back his laughter. "You _know_ what I'm talking about, because you _told_ them about this... this... blatant _lie_!" She ended with more beating via the pillow.

He held up his hands in defense from the pillow-y blows. When she'd finished her round of attacks he put on his best 'fake innocent' look.

"Casey; I fail to see how any of this is my fault." He paused and she glared at him, "I mean... if you would've just _abstained_... none of this would've been an issue." He finished and her eyes widened and she hit him with the worst blow yet; to the face. "_Oof!_"

He actually fell backwards from his sitting position on his bed.

This seemed to startle her, as she abandoned the pillow and rushed towards him, taking a seat next to him.

"Oh my gosh! I'm so sorry, are you okay?" She asked him, her hands grabbing at his arms and pulling him back up, to sit.

To this, he just laughed.

Because... really? Yeah it stung for a second and it knocked a bit of wind out of him but... it's a _pillow_, and- and he just spread a vicious rumor about her. She should he _happy_ about her victorious fluff-attack.

"Why are you laughing?" He just laughed s'more and fell backwards again, "_What_ is so funny?!" She asked, getting annoyed all over again.

He took a break between his laughter to simply say, "you."

And she kinda-sorta _didn't_ want to smile at him; but it seemed to be a losing battle as she let herself even start to _giggle_ a bit.

And before either of them knew it, she was collapsing beside him on the bed, giggling uncontrollably. His laughter must've been contagious..._ or something_.

So there they were, laughing and squirming until their eyes were wet and their bladders seemed ready to explode.

"Why did I come here in the first place?" Casey asked as she was calming down a bit.

"I don't know, but my guess is that you were reprimanding me for something, _mom_." He replied jokingly.

"Shut _up_." She said, regaining her memory a bit more. "Just tell me why you told all those guys that I had..."

"Crabs, Casey." He paused and she stiffened for a moment, "You have crabs." He told her, sitting back up, once more.

"Der-_ek_!" She swatted him, sitting up as well, "I do _not_." She was still reeling from the giggle-fest, so it didn't come out as angry as she would've liked.

"You keep telling yourself that." He joked. The next thing that happened... well let's just say _no one_ was expecting it.

She tackled him down on the bed. And straddling him, she pinned his arms above his head, sending a murderous glare towards him.

His eyes widened as she spoke, "I. Don't. Have..."

"Crabs." he finished for her, his eyes now beginning to return to their normal state.

"Yeah. That... and you're going to tell me," She paused and he gulped (he _wasn't_ nervous. he _wasn't._), "what on _Earth_ compelled you to tell just about _every_ guy on campus that I _did_ have..."

"Crabs."

"Thank you, Derek. We've gotten the point. Now spill."

_Trapped._

Until now, Derek _did _have a plan: avoid the topic at all costs, and if it was brought up, make it into a joke. But-uh... that didn't really seem like an option anymore. So he just sat there.

"Derek. Come on!" She whined, "There has to be a reason." And... she looks... _desperate_. He thinks that maybe... just _maybe_... for a _second_... that he could just _tell_ her the _truth_.

But then she's shaking him.

She _actually_ grabbed his shirt and started yanking him up and down and maybe it's just _him_, but _some_thing about the situation wasn't... _right_.

"Casey!" He finally spoke- well, yelled really- and he felt something wet fall to his cheek.

She was... _crying_?

He _wants_ to just _smack_ her, 'till she regains her senses, but he knows that just wouldn't work(not to mention, he wouldn't be able to hit her-'cause she's a girl. That's all.). So instead he sighed and took hold of her arms, delicately.

"Jeez, Case. Just Calm down." He spoke gingerly. (He'd never admit that he _actually_ cared that much, but... maybe he did.) No, he didn't care. That's all there was to it. But then, "I- I'm sorry... okay?" _What_ was he _saying_?! Because his mouth _obviously_ wasn't listening to his mind. Or else it wouldn't have _willingly_ apologized to her that easily- or at _all_. Right?

But then, he moved his hands up to her face and wiped her tears. "I didn't know it would upset you this much..." _Damn_, he's soft.

She avoided his eyes as she spoke, "I'm not crying because of that, _Moron_." But the 'moron' wasn't insulting; more endearing, really.

"Well, then why _are_ you crying, you big _loser_?" He rebutted with his own insult-less insult.

She gave him a half-glare. "I don't know..." She lied. He gave her a pointed look and she grimaced. "It's nothing," _sniff_, "really."

"Casey..." and he's wondering if he's even said anything other than her name this entire time, because it's pretty much all he can remember saying.

Then she looked at him. Which she definitely _shouldn't_ have done, they both concluded, because she saw the look in his eyes and... and her lip was quivering again.

_Sigh_, "Casey, please. Just stop crying..." He rubbed her back and she leaned into him.

And oddly enough... despite the tears... this just... felt right... to him.

Oh and it had _absolutely nothing_ to do with the fact she was _still_ straddling him.

With all of her weight on him, he just laid there, consoling his step-sister.

It seemed like forever before she sat back up, which may not have been such a smart move on her part because as she elevated herself she rubbed against Derek's... well... you get the picture.

He managed to contain himself for the most part and she didn't seem to notice as he thought of baseball, and old grannies, and oh yeah; their parents. Yeah, the ones that were having a baby together sometime in the near future (he wasn't really interested in specifics at the moment).

"I'm sorry, Derek. I know you hate tears."

"S'okay." He replied shortly(he had other things to worry about), staring straight ahead at the ceiling.

"Wh- what's the matter?" She looked at him with furrowed eyebrows.

"M'Nothin'." _Baseball, the Red Sox, Nora and George with their..._bundleof _joy. _Oh joy(did he forget to mention sarcasm was his _best_ friend?).

"No, there's- there's something wrong. Wha...?" She looked around her, as if trying to find an explanation from elsewhere in the dorm room. Although, in doing so, she kept swaying her hips back and forth, and he just... _couldn't_ take it.

He grabbed her hips to keep them in place. "Casey." His voice was low, and she just _still_ didn't get it. He didn't want to say anything else though, or it may sway his concentration. The end result? A freaked out Casey and a _really_ cold shower (at 1:49 in the morning).

"What is it? I don't..." her voice trailed off and she _still_ just didn't understand. So he closed his eyes, and just kept imagining horrible things that would just turn him the _hell_ off. Grandparents, more baseball, _anythingggg_, just why wouldn't it go away? "Derek?"

Maybe if she would just _stop_ talking for once in her life, he could stop imagining her in... _wait_, imagining her!? _Damn_, he's in deep.

But he still didn't say anything, and it was getting harder to contain himself. He'd stilled her rocking hips, but her mouth was still flapping away, and he just needed to _get out_ of the situation.

"Derek, what is wrong? Why aren't you saying anything?" And her face was _damn_ close to his, that it was almost... _inviting_. Then he's thinking: Why _is _her face so close to his? And... Why _is_ she still on top of him?

So then he's saying, "You're still on top of me?" And it comes out as kind of a question. But _not_ at the same time... because part of him just wants to know if she noticed or not.

"Oh- uh... yeah." She chuckles nervously, but doesn't move. And why won't she just... _move_? But he doesn't want her to move, really. Not only because if she _does_ move and doesn't move the _right way_, something may happen, and he just... doesn't want to... well... be that guy- but also because he just _likes_ her there. But what's _wrong _with him?

"Yeah." He breathes. And this is the most he's talked in about ten minutes, so... she probably thinks it's some sort of breakthrough. "Maybe you should uh... _get off_." He says, and his double meaning doesn't sink into _her _brain, but... he sure as hell caught it, and he shouldn't, _shouldn't_, shouldn't be thinking about her... _getting off_.

"I uh... I can't." She says. And he actually looks at her, because... _why the hell not!? _And she gets the look on his face, because she looks down, "You're uh... your hands are..." She trails off.

He looks, and realizes, he never moved his hands from her hips. _That's_ why she was still there. Then there's this sinking feeling in his stomach because, he really wanted there to be a different reason.

"Oh." And he moves his hands.

She still doesn't move.

"Um..." He says awkwardly.

"I never told you why I was crying." She speaks. And it catches him off guard because he was _sure_ they were both up to date of the awkwardness of her constant state of... straddling him.

"Uh..." He can't really speak, because the thought of her crying made him kind of_ forget_ about the awkwardness as well, and he... well, he was just thrown off.

"I guess I'll just tell you, considering..." She didn't really need to say the rest because of what followed, "I _wanted_ there to be a reason for you telling those guys I had..."

"Crabs." He interjected impulsively.

She laughed. "Yes." She paused, "I just... need to know why you told them, Derek."

"I don't think now's the time, Casey." He spoke with slight urgency in his voice.

"I think now's the _perfect_ time, Derek." She said, moving her hips a bit.

That's when he realized... she was a _tease_.

He closes his eyes on reflex. "Casey. Don't."

"Why not, Derek? Afraid a little _truth_" another swaying of her hips, "is going to come out in the process?"

"Mm-no." He breathed.

"Then tell me, Derek. Just _tell_ me why you told them that?!" She started raising her voice, and the voice in his _head_ was screaming as well.

"Fine!" He yelled. And she smiled endearingly at him. "You want to know why I told those guys you had..."

"Crabs?" She finally spoke.

"Yeah." he paused, and she nodded for him to continue, "It's because I didn't want you dating any of them, okay?!" He answered, angrily.

"Why not? I'm my own person! You can't play protective, older brother for me forever, Derek." And his eyes widened.

"Bro- Casey are you nuts?!" He screamed, sitting up a bit, but she was still sitting in his lap, legs wrapped around his torso. She didn't respond. Only waited for more insults, more of... anything. "What kind of brother does _this_?!" And he did it. He kissed her.

It was hard, and rough, and pretty much just like every other aspect of their relationship. He hadn't even realized it, but she was kissing back. It wasn't perfect. It was sloppy, and unplanned, and he just wanted to tell her everything he was feeling through that one kiss. _But so did she_.

"That was a test, wasn't it?" he asked her when they pulled away from each other.

"Maybe, maybe not." She smirked, and he shook his head in disappointment at himself for being outsmarted. "But if it was, you passed."

"Oh, yay. First thing I've passed all semester." He joked.

She smacked his chest before leaning in for another steamy kiss.

It was getting pretty hot and heavy and Casey was clawing at the bottom of his shirt in attempts to just... _rip it off_, or something. Derek definitely liked where things were going but he couldn't help but think he may be taking advantage of her- which he just _didn't_ want to do. At least not with her. Not with Casey. She deserves better.

So as she gave up trying to remove Derek's shirt in attempts to subtract her own, he stopped her mid-undress.

"I don't know if this is best, Casey." He started, "I mean... I heard you had..." He leaned closer, "Crabs." it came out as a whisper, his eyes widened for emphasis.

"Shut up and take it like a man, Venturi." She shoved him back down and took off her shirt.

* * *

First thing's first: he flips her over. Because there's _no way_ he's letting her be the one in control.

They're kissing, for a really, _really_ long time. He doesn't know how long, but his tongue is starting to lose feeling. So he pulls away from her lips- because he may _need_ his tongue later. For... _other _things- and places light, feverish kisses along her jaw line. He continued his ministrations down her neck, nipping lightly at her skin every now and then.

She moans softly, and he's just... _amazed_ that he's the one to make her excrete such _noises_. So he continues, down to her chest, and lets his lips hover over the outline of her bra - all the while, reaching behind and unclasping the hook. With one swift movement, he discarded the garment onto the floor, taking one of her breasts with his mouth and the other with his hand. Casey arched her back in pleasure, as he switched activities with ease.

Not wanting to stay in the same place for too long, Derek ventured further, lips grazing the soft skin of her stomach before making his way back up to her mouth, capturing it with his own. His hands roamed wildly over her body and she just felt... _amazing_ to him.

She gasped quietly as his hands caressed her inner thigh; even through the thick fabric of her jeans, his finger held this magic to them that just made her _melt_. Deciding that they just _needed_ to be closer, they rid themselves of the rest of their clothing in stride.

"Are you sure this is what you want?" Derek whispered, his breath hot on her neck as his hands rested along her lower back.

"MmmPositive." She mumble breathlessly.

A low chuckle escaped from Derek as he said, "That better be the _only_ thing about you that's _positive_."

"Shut it." She smirked at him, wrapping her legs tightly around his hips.

"Mmm. Whatever you say, Crabby- I mean, Casey."

She laughed in that _bedroom_ sort of way, before he took her mouth with his own again.

* * *

Then they're laying next to each other; sweating, breathing heavily, and just _thoroughly_ _enjoying_ their current state of euphoria.

"Well..." He spoke, still trying to catch his breath, "I'll say this," _breathe, dammit_; "If it turns out you _do_ have crabs... it was _damn_ worth it." He paused, "But you're _paying_ for that special shampoo and the comb, you know. 'Cause it'd technically be all your fault."

"Yeah... well... it's a good thing you say that 'cause..." She trailed off.

"Wh- wait; _what!?_" His mouth fell open as he flipped himself on his side instantly to gape at her.

"It was a _joke_, Moron." She turned on her side as well, although, she happened to be a bit more graceful than he was.

"Well, you big _loser_, I don't think it was funny!" He said, his own laughter betraying his words.

"Just shut up, Derek." And she made _sure _he shut up, by silencing him the best way, possible: with a kiss.

"MmmMPHmmPHRMM" He rambled on, as they were kissing. She pulled back.

"God, you're hopeless." She rolled her eyes, kissing him again.

He replied simply with a smirk against her lips, giving in just this _one time_.

* * *

A/N: So I don't really like the ending but... whatevs. haha Tell me whatcha think! :)


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